ASCO: Preliminary advanced STS trial

A pilot study evaluating the safety, tolerability, and efficacy of doxorubicin and pembrolizumab in patients with metastatic or unresectable soft tissue sarcoma.

Abstract No : 11519

Abstract Type : Poster session

Indication : Soft Tissue Sarcoma

Intervention : doxorubicin + pembrolizumab

Company : Merck & Co.

Technology : Small molecule/monoclonal antibody


From 4/2017 to 12/2019, 30 subjects (53% female, median age 61.5 years, 10 patients . 70 years (33%)) were enrolled in the study with 6 (20%) patients still on treatment and 27 evaluable for response. The most common histologic subtypes were leiomyosarcoma (33%) and liposarcoma (23%), and a majority of patients demonstrated high grade disease (60%). Current analysis shows a median follow-up of 9.9 months. One subject experienced a stopping rule event (grade 3 autoimmune disorder). ORR was 33% (95% CI 17-54%), with documented disease control in 78% (95% CI 57.7-91.4%) of patients. Eight (30%) patients achieved a partial response, one (4%) patient achieved a complete response and 12 (44%) patients had stable disease. Preliminary results demonstrate median PFS of 6.9 months (PFS-6 mo: 52%) and median OS of 15 months (OS-6 mo: 81%) compared to historical PFS-6mo of 4.6 months and OS of 12.8 months with doxorubicin alone.1 Most common grade 3+ TEAEs included neutropenia (11 [37%]), febrile neutropenia (6 [20%]), anemia (5 [17%]), and nausea (4 [13%]). Molecular and biomarker analysis is currently in progress


The combination of pembrolizumab with doxorubicin has manageable toxicity and preliminary promising activity in the treatment of anthracycline-naive advanced soft tissue sarcomas.


With ORR of 36% a new combination can emerge as a new standard of care in soft tissue sarcoma.The findings from the trial may lead to a wider phase 3 trial for further validation of this data.

Refer to Soft Tissue Sarcoma Market report for detailed Insights.